Optional steps

For graphical desktops, systemd independent udisks2 and/or policykit will be pulled from the repo above.

Using Debian Installer preseed.cfg

If you're installing a number of Debian machines you can use a preseed file to set up custom settings.
This is especially useful for unattended installs, for instance for KVM guests.
The easiest way to get settings into the post-install routine is via a script. In this example the script will be served by a local web-server running from apt-cacher-ng. In my case, this server runs on the local address 192.168.122.1, which is also the local DHCP server that the KVM instances get their IP addresses and hostnames from.